A Novel Helical Slow-Wave Structure of a TWT With Increased Number of Helix-Support Rods for the Suppression of BWO Caused by Thermal Deformation

Abstract

Backward-wave oscillation (BWO) is one of the important factors affecting the output power and operating stability of helix traveling-wave tubes (TWTs). A novel helical slow-wave structure (SWS) with six helix-support rods at the end of SWS of TWT is proposed to suppress BWO caused by thermal deformation. An electrical–thermal–mechanical finite element coupling analysis model for the TWT is established. The simulation analysis shows that the maximum temperature at the end of the helix is reduced by 49 °C, the maximum thermal deformation is reduced by 56%, and the saturated output power at 11 GHz is increased from 464 to 519 W. The analysis confirms that the novel SWS can effectively suppress BWO caused by thermal deformation in a high-power TWT and improve the TWT’s output power and operating stability.